Passenger cars now have very high performance, because many improvements have been made to engines and other mechanical or electrical elements of the cars. For example, the power output of engines is enhanced and body weight is reduced. Also, starting, accelerating and cornering properties are significantly improved.
As the properties of the cars, the power output of the engine, which indicates the horsepower of the car, and body weight are important, but the way how they are characterized or classified is different by each motor-manufacturing company. It is also important in view of safety that the tire which is suitable for the car are selected according to the performance of the car, whereby the performance of the car can be adequately drawn out.
However, in the development of the tires, especially in the development of the tread rubber which greatly contributes to the properties of the tires, it has not been considered to satisfy the performance of the car, excepting the tire for very special cars. Actually, in order to balance grip properties, comfortability to ride in, wearing resistance and the like, some rubbers are mixed to find a compromise point at the sacrifice of the properties of each rubber.